The following comes from the City of Pelham: 

Gypsy Moth home maintenance
Pelham will see another heavy infestation year for gypsy moths in 2020. Below is a list of a few things you can do for trees on your property to help protect from defoliation. And if you want to stay up to date with all of the latest information about this year’s gypsy moth aerial spray program, policies, and more, make sure to visit: www.pelham.ca/gypsy-moth and subscribe to the page so that you never miss an update.

What you can do:

Gypsy Moth is in the egg stage between early September and late April. Egg masses can be found on tree trunks, branches, buildings and on objects around the house. As one egg mass contains about 300 eggs, by destroying them you significantly reduce the number of caterpillars that emerge in spring.

Scrape off egg masses with a dull knife and place them in soapy water for a few days before discarding them in the garbage. If they fall to the ground crush them with your shoe.

Late April to Late May – Place sticky barriers, or bands on the tree trunk

Wrap duct tape around the tree trunk and apply a thin coat of sticky material (commercially available at most garden centres) to the duct tape. Alternatively you may use a double band of duct tape, the outer band with the sticky side out. This band will prevent smaller caterpillars from climbing the tree.

Mid-May to Early June – Spray with bacterial insecticide, Bacillus thuringiensis ssp. kurstaki (Btk).

The primary objective is to protect vulnerable trees from moderate to severe defoliation. Reducing the nuisance factor caused by the presence of gypsy moth is an additional benefit of this treatment Consider having your trees sprayed with Btk by a licensed pesticide applicator if:

There are a high number of egg masses that cannot be removed mechanically from the trees.
Large numbers of egg masses are on susceptible tree species, primarily on oaks, birches, beeches and spruces.
If damage that is caused by gypsy moth feeding is severe for at least one or two previous years, another severe defoliation event may cause the decline or death
of the host tree.

Late May to August – Replace sticky bands with burlap (cloth) bands.

Trap and destroy caterpillars by placing burlap (cloth) bands on trees. Wrap burlap that is approximately one metre wide around the tree trunk, tie it at the middle with a rope and fold it. Caterpillars feed at night and find shelter from the heat during the day. They will congregate under the burlap. Destroy caterpillars from under the burlap every late afternoon before they crawl back to the canopy to feed.

Caterpillars can be killed by squishing them or placing them in soapy water. Use this method until all the caterpillars finish their life stage, usually in August, and turn into cocoons and laterinto adult moths.

Rice Road Greenhouses sells products which can help to protect your trees from Gypsy Moths, including: Tree Guard Tape, Tangle Foot, and the TangleFoot Tree Care Kit.